Wedge clamp mechanism



April 3, 1951 L. SKEE 2,547,7s9

WEDGE CLAMP MECHANISM Filed Dec". :51, 1946 3 Sheets-Sheet 1 INVENT LEW/5 5K5 A m 3, 195a L. SKEEL 2,547,789

IN E TOR. LEW/S Sh EL.

Patented Apr. 3, 1951 WEDGE CLAMP MECHANISM Lewis Skeel, Meadville, Pa., .assignor to Robert W. Thomas, Meadville, Pa.

Application December 31, 1946, Serial No. 719,535

7 v13 Claims. I

The present invention relates to devices for looking or adjusting the blades or cutters of mills, boring bars, and the like, wherein the cutting 'or boring operation is accomplished by a rotation of the tool body or holder. They are also applicable for the same purpose in conjunction with tools and stationary or non-rotating tool holders, such as are found in lathes and shapers. While the invention will be specifically described in connection with the tool body of a mill its application thereto is not to be construed as a limitation thereof for the reasons just given.

This application is in part a continuation or my copending application Ser. No. 607,946, filed July 31, 1945, and now abandoned,'the entire subject matter of which is carried forward here and enhanced by the addition 01' several valuable modifications.

In its general aspects the invention contemplates the provision of one or more blade receiving slots in a tool body or holder for the reception of one or more cutting-blades or tools and a corresponding number of cooperating blade securing devices, each arranged in the form of a unit or assembly insertible in the tool body adjacent the blade. The blade securing device includes a carrier, one or more wedge elements, and operating members whereby these parts are :moved relatively so as to lock securely the blade or tool in the desired position. On the other hand when it is desired to adjust or remove. a blade it is only necessary to move the operating member a limited degree to effect a relief of the blade locking pressure. Under these conditions the blade securing device as a unit may remain in the tool body.

it is a major object of my invention to intercouple the carrier and its associated wedge ole-.- ment bythe operating member so that these three parts form a unit; and, in this connection, it is an object to so design the locking unit with relation to the blade that this unit may beinserted or detached bodily without removal of the blade,

Further advantages of the invention will appear in the following detailed description wherein corresponding marks of reference will appear in the drawings, in which:

Figure 1 is a transverse section through a tool body showing .an insertible blade and the blade securing device in free or non-"locking position.

Figure 2 is a view similar toFigur-e 1 but showing the blade securing device in blade locking position.

Figure 3 is a perspective view of the blade se curing device of Figures 1 and 2 as it would appear removed from the tool body.

Figure 4 is an enlarged view, similar to Figure 2,. in the opcrating member. i Figure 5 is a plan view illustrating a modified showing the screw difierential utilized arrangement of the invention usable in conjunction with a blade slot widened to receive the blade or tool and the securing device.

Figure 6 is a view .similar to Figure 2, showing a modification wherein the wedge is drawn up to engage the blade instead of being pushed down,

as in Figures 1 to 5.

Figure 7 is a similar view of a form wherein the socket is in the top of the carrier and contains a wedge that is drawn down to engage the blade.

Figure 8 shows another modification with the socket in the bottom of the carrier but so arranged that the wedge is pushed down against a wall of the tool body instead of the blade.

Figure 9 shows in general a reversal of the parts of -Figure 8 so that the socket is in the top of the carrier and the wedge is pushed up against the tool body.

Figure 10 represents another form, similar to Figure 8, but modified so that the wedge is drawn up to engage the tool body.

Figure 11 shows still another modification, similar to Figure 9, but designed to cause the wedge to be drawn down.

Figure 12 is a view similar to Figure 5, showing that an elongated carrier may be utilized with a plurality of wedges engageable with the tool body instead of the blade.

Referring first to Figs. 1 to 4 of the drawings,

which are carried forward from said earlier application, a tool body I is slotted parallel or at may be a single slot and blade therein; in a milling cutter of the common type there may be a series of slots'and blades therein, but in any event the characteristics of the invention remain the same.

The rear'faces or walls of the slots and blades may be serrated or grooved as shown at 4 in aid of adjustment or retaining the blade in fixed position.

Opening into the side of the slot 2 opposite the:

serrations 4 is a cylindrical recess '5 the axis of a which is parallel to the walls of the blade slot and lies in a vertical plane as shown in Figures '1,

2 and 4.

The recess 5 is occupied by the blade securing device 6 which embraces a carrier 1, a wedge element 8 and an operating member Ill. The car-- rier I is cylindrical in shape except for a flattened portion I I and is fashioned to conform with and has a sliding fit in the recess and against the front surface of the blade 3. The lower portion of the carrier is provided with a socket I2 open to the flattened portion II and is established by the top wall I3 and a cylindrically curved side wall I4. The axis of the socket is inclined in respect to the axis of the recess 5 toward the flattened portion II of the carrier with the result that the socket opening I5 in the flattened surface II of the carrier takes a trapezoidal form with the longer side of the trapezoid at the base of the carrier. The rear wall I4 of the socket is also inclined toward the flattened surface I I of the carrier 6 and the front face of the blade 3.

The wedge element 8 is cylindrical in shape and is provided with a flattened surface I6 arranged at an angle to the axis of the element to produce a trapezoid of slightly less dimensions but corresponding to the trapezoidal opening I5 of the socket I2. The overall height of the element 8 is somewhat less than that of the socket. The relative diameters and other dimensions of the socket and wedge element are by preference such that the wedging or locking action of the element becomes effective substantially midway of the socket or at a point where sufficient clearance exists between the upper and lower ends of the socket and element. This relationship will provide for an easy loosening of the parts for blade adjustment or removal and at the same time afford room for compensation of loss of fit due to wear of the parts.

The cylindrical curvature of the wedge element is further important in that it permits the wedge element to rockably adjust itself to ensure full surface contact between its flat face and the blade. This is true also of other forms yet to be described, whether the wedge engages the blade or a wall of the tool body.

The operating member II] as herein disclosed takes the form of a differential screw established by utilizing different values of a helix. This preferably is accomplished by forming the screw so as to have sections of greater and less diameters with complementary threads of different lead values. The axis of the screw is inclined with respect to the axis of the carrier I and the front face of the blade 3. The screw section I! of larger diameter is provided with a relatively coarse thread of substantial lead value working in complementary threads in the carrier I and the screw section I8 of smaller diameter is provided with a relatively fine thread of less lead value working in complementary threads in the wedge element 8. The exposed end of the screw may be recessed or otherwise formed to receive a turning tool or wrench. As will be seen from the drawings there is a substantially uniform distribution of the metal of the carrier and wedge element about the screw threaded openings therein.

The axis of the socket in the carrier must be in parallelism (includin coincidence) with the axis of the tapped hole in the carrier and preferably is aligned with the axis of the threaded hole in the wedge element. Thi arrangement provides a common axis for the socket, screw and wedge element. The concentricity of these three parts makes it possible to rotate the wedge element in the socket to establish the correct lineal relations between the carrier, screw and wedge element before inserting the assembled device in the recess-so as to predetermine the correct starting point for applying the pressure of the wedge element against the blade. The concentricity of the socket, wedge element and screw will also permit using a common screw-machine technique in the manufacture of the carrier and the wedge element on a production basis.

When the several parts of the blade or tool securing device are assembled and the wedge element 8 is drawn to the top of the socket I2 in the carrier 1, the flat face I6 of the wedge element is flush with or slightly under the plane of the flat face II of the carrier and the upper end of the-screw I0 extends several threads above the top of the carrier. When the parts of the securing device are in these related positions, it can be dropped into the recess 5 in the tool body and will come to rest at the bottom of the recess without any interference between the securing device and the recess or between the securing device and the blade.

' To apply locking pressure against the blade or tool, the differential screw II] is advanced into the carrier I according to the larger or faster lead value of the threaded section I'I. At the same time the smaller and slower threaded section I8 having a less lead value turns within the wedge element 8; The corresponding differential in the lead or lineal travel occasioned by the fast and slow lead of the screw sections I1 and I8, respectively, produces a relatively slow advancing or wedging action of the element 8. The net effect of these conditions may be likened to the advance of the wedging element under the influence of a single fine thread of low lead value. However, such a thread is unsuitable to meet the heavy load and shock effects occurring during operation of the blade or tool in addition to the liability of injury to such a thread while handling the same. On the other hand the differential thread construction here disclosed permits a very slow or fine feed of the wedge backed by the strength or mechanical endurance of relatively fast or coarse threads on the operating screw I0.

While the wedge element is being advanced by the screw the inclinationof the back wall of the socket in the carrier forces the flat face I6 of the wedge element outward laterally and slightly beyond the plane of the flat face I I of the carrier. This action brings the flat surface I6 of the wedge element into contact with the blade or tool and increases the locking pressure against the blade as the wedge element is forced farther down toward the bottom of the carrier by the differential screw.

The angle at which the wedge element is flatted is such in relation to the rear wall of the socket in the carrier that the flat face I6 of the wedge element is always parallel to the axis of the recess 5 in the cutter body and therefore parallel to the blade. As a result the flat face I6 of the wedge element has a full bearing on the blade or tool.' g

The inward inclination of the socket of the carrier wedges the descending wedge element between the blade and the carrier preventing the action of the differential screw from raising the carrier in the recess 5 of the cutter body.

' By retracting the differential screw the wedge element is raised in the socket and away from the blade leaving the blade free to be adjusted in the slot or removed from the body without removing the blade or tool securing device 6 or any part thereof.

The invention may be realized by a slightly dif- 5. ferent arrangement as shown in Figure. 5. Instead of using a blade slot of a width. approximating the width of the blade or tool and. a. sepa rately' formed. recess. for the reception. of. the blade securing device as shown in Figures 1, 2 and 4,. a tool: slot orguide sufiiciently'wide may be formed in the tool body to receive the blade and its securing device, thus eliminatin the extra machining operation: necessary to form: the recess shown in Figures; 1, 2' and 4.. To this end, as shown in Figure 5, a slot 2a. is formed in the tool body la to receive the blade 3a and the bladesecuring device 6a, their combined widths being such as to fill r occupy substantially the width of the slot. As here shown, the carrier la may be generally rectangular in cross-section with one or more sockets and threaded openings formed therein to. receive. the wedge element and operating member, respectively, and. arranged at an.

angle to the adjacent face or side of the blade as shown in Figures 1, 2 and 4.

The arrangement of Figure ofiers several advantages. A singl milling operation will form a slot or recess common to the blade and its securing device. While a single securing device applying locking pressure to the blade at a single or localized zone is adequate for a relatively short blade or tool and. is contemplated for use in conjunction with. the common. slot arrangement, a

relatively long blade or tool may require locking pressure at. several points to maintain the blade substantially rigid and to compensate for any irregularities or inequalities in the slot. Under these circumstances the single. carrier T0. with. its multiple sockets,v Wedge. elements and operating members can be advantageously used. Securing devices of the single or multiple type may be used side by side if the occasion requires. They may be kept in supply and used in any number of tool bodies having adequate slots 0r recesses, thus eliminating the necessity of producing a particular securing device for a particular tool body.

The action of the wedge element oilers operating advantages. It permits the operator to lock or unlock the blade or tool quickly and easily without hammering either the blade or the tool body. If a plain blade is used, the downward movement of the wedge element tends to force the blade to a firm bearing against the bottom of the slot. seating of a blade with vertical serrations that engage corresponding vertical serrations in the rear wall of the blade slot. The sidewise fullbearing pressure of the Wedgeelement also makes the device suitable for locking blades with horizontal serrations asherein shown.

If plain blades or tools with horizontal: serrationus are used, adjusting screws threaded into the body behind the blades will usually be incorporated. in the. cutter design. The device: asv

described above will assist: the use of these-screws to adjust the blades preparatory to regrindin-g. Thelocking pressure of the wedge element. is gradually and evenly increased or decreased as the diiferential screw is advanced or retracted. The 1 correct pressure that will permit: the blade to be moved or adjusted and still keep it tight against The same protection is given to the erated. with: one simple end milling operation. This of course: also is true of the modified. forms of Figs. 6to1 1, about to be described.

Inv the, modified form shown in Figure. 6-,, the parts. 622,. 8b, etc; correspond to parts 6, 8,. etc. of Figures 14-, the changes in design being such that the screw and socket axes are inclined toward instead of away from the outer edge of the blade. Here the wedge must rise instead of descend to cause the blade to be locked in position, and this is accomplished by placing the coarse threads on the inner portion or-section of the operating screw. It follows that the wedge is drawn upwardl when the screw is rotated in a tight ening direction.

Figure '7 illustrates another modification, wherein the socket l2-c is disposed in the top of the carrier instead of in the bottom thereof. The axis of the screw 100. has approximately the same tilt as. in Figs. 1-4, and the wedge must move downwardly to eiTect a blade lock. The wedge is drawn down by placing the coarse threads on the inner section of the screw. This. form has advantages in certain kinds of work in that the upper or cutting edge of the blade is held more rigidly against the adjacent face of the slot in the toolbody.

In the embodiment shown in Figure 8 the wedge element 811 is forced into engagement with a wall of the tool body, instead of the blade 3 as in the previously described forms, which in turn forces the carrier 6d into binding contact with the. blade. The Wedge socket I251 of the carrier id opens laterally towarda flat wall 29 of a modified recess 5a. The wedge 8d, has its fiat surface presented to the wall 28, its other surface remaining a partial. cylinder in contact with a mating cylindrically curved surface within the socket IZd.

However, with continued reference to Figure 8 and to similar forms to follow, it should be understood that the body wall 2!] and associated faces of the carrier and its Wedge may be curved instead of flat; or that the parts may be complemented in various other ways so long as the wedge is capable of being moved up and down and acts to force the carrier laterally. In this form, the Wedge is pushed down to lock the blade in position.

In the form shown in Figure 9 the wedge be is pushed up by the screw Hie for locking purposes. This arrangement, with the socket lie at the upper or outer end of the carrier 56 and facing laterally away from the blade, is highly desirable because the wedge can have no tendency to lift the blade when it is tightened and it applies the greatest locking pressure adjacent the outer (cutting) edge of the blade.

Figures 10 and 11 with their parts 6'), etc. and do, etc., respectively, represent still further forms in which the wedge engages a wall of the tool body insteadof the blade. In Figure 10', the screw threading is such that the wedge is drawn up for tightening. In Figure 11, the wedge is drawn down to eiiect a lock.

Figure 12. is similar to Figure 5 in that an elongated carried 6h is set into the body ta alongside the blade 3a and in; parallelism with. a fiat body wall. surface 21 that forms: one side of the carrier and, blade slot. Two or more spaced locking units are fitted into this elongated carrier and designed so that their wedge elements engage the Wall 2| instead. of the blade, as in Figure: 5-. The parts shown 89, mg, correspond to those of Figure 11 but it. will be understood that the forms of Figures 8, '9 and 10 may be' used with equal facility. This embodiment is par ticularly advantageous for locking cutter blades made from solid carbide because the locking pressure is distributed uniformly by the fiat or plain face of the elongated carrier bearing against the blade in contrast to the localized pressure that would be applied by engagement of the wedges with the blade.

I claim:

1. A unitary locking device comprising a carrier element adapted for insertion between a pair of members which are to be locked against rela tive movement, said carrier element having at one end an inclined socket that opens laterally, the side wall of said socket being cylindrically curved, said carrier having a side locking surface, a wedge element in said socket and having a cylindrically curved side wall portion mated to said socket side wall and a smooth side locking surface exposed adjacent the lateral opening of said socket, said side locking surfaces being adapted to engage said members when the device is assembled therebetween, and operating means for slidably moving said wedge element axially of said socket.

2. A unitary locking device comprising a carrier adapted for insertion between a pair of members which are to be locked against relative movement, said carrier having a side lockin surface and further having a cylindrically curved socket, a wedge element movably mounted in said socket and having a cylindrically curved side wall portion mated to said cylindrically curved socket and also having a side locking surface, said side locking surfaces being adapted to engage said members when the device is assembled therebetween, and an actuating screw threadedly mounted in said carrier and threadedly connected to said wedge element for actuating the latter, the threaded connection between said screw and said wedge being of a different lead than that between said carrier and said screw.

3. A unitary locking device comprising a carrier adapted for insertion between a pair of members which are to be locked against relative movement, said carrier having an inclined socket that opens through one side of said carrier, a wedge element mounted in said socket for axial sliding movement from an inoperative position within the confines of said carrier to an operative position wherein it projects laterally through the open side of said socket and beyond said carrier to effect locking action of the device, and a differential screw threaded into said carrier and into said wedge element for interconnecting the same and moving said wedge element from its inoperative to its operative position and vice versa, the threaded connection between said screw and said carrier being of a different lead than that between said wedge element and said screw.

4. A unitary locking device comprising an elongated carrier adapted for insertion between a pair of members which are to be locked against relative movement, said carrier having a side locking surface and further having an inclined socket that opens laterally, the side wall of said socket being cylindrically curved, a wedge element slidably mounted in said socket and normally disposed within the confines of said carrier, said wedge element having a cylindrically curved side wall portion mated to said cylindrically curved socket side wall and further havinga side locking surface exposed adjacent the lateral opening of said socket, and a rotatable actuating screw threaded into said carrier and into said wedge element for interconnecting the same and moving said wedge element from an inoperative position within the carrier to an operative position wherein it projects laterally beyond said carrier to effect locking action of the device, the threaded connection between said screw and said carrier being of a different lead than that between said wedge element and said screw.

5. In the structure defined in claim 4, said carrier being partially cylindrical and the side locking surface thereof being flat and extending for the full length of said carrier, said socket being at the outer end of said carrier and opposite said side locking surface, said screw having threaded portions of two diameters, the larger portion being rotatably mounted in said wedge element and having the thread of greater lead.

6. A unitary locking device comprising a carrier adapted for insertion between a pair of members which are to be locked against relative movement, said carrier being partially cylindrical and having a fiat side locking surface extending for the full length thereof and further having a socket at one end that opens laterally and is dis-.

posed opposite said flat side locking surface, the side Wall of said socket being cylindrically curved, a wedge element mounted for axial sliding movement in said socket and having a cylindrically curved side wall portion mated to said cylindrically curved socket side wall and further having a side locking surface exposed adjacent the lateral opening in said socket, and an actuating screw threaded into said carrier and into said wedge element for interconnecting the same and actuating said wedge element to force said side locking surfaces into and out of binding engagement with said members when the device is assembled therebetween, the threaded connection between said screw and said carrier being of a different lead than that between said wedge element and said screw, the axes of said socket, said wedge element and said screw being coincident and inclined to the axis of said carrier.

7. A unitary locking device comprising a carrier adapted for insertion between a pair of members which are to be locked against relative movement, said carrier having a side locking surface and further having an inclined socket that opens laterally, the side wall of said socket' being cylindrically curved, a wedge element mounted for axial sliding movement in said socket and having a cylindrically curved side wall portion mated to said cylindrically curved socket side wall and further having a side locking surface exposed adjacent the lateral opening of said. socket, and an actuating screw threaded into said carrier and into said wedge element for inter-' connecting the same and actuating said wedge element to force said side locking surfaces into and out of locking engagement with said members when the device is assembled therebetween, the threaded connection between said screw and said carrier being of a different lead than that between said wedge element and said screw.

8. In the structure defined in claim 7, the side locking surface of said wedge being flat and the side locking surface of said carrier being cylindrically curved, said socket being at the inner end of said carrier, said socket and said wedge decreasing in cross-sectional area toward the inner end of said carrier, the threaded connection of greater lead being between said screw and said carrier.

9. In the structure defined in claim 7, the side locking surface of said carrier being fiat and extending for the full length of said carrier,

said socket being at the inner end of said carrier and opposite said flat side locking surface, said socket and said wedge decreasing in crosssectional area toward the inner end of said carrier, the threaded connection of greater lead beingbetween said carrier andsaid screw.

10. In the structure defined in claim 7, the side locking surface of said carrier being fiat and extending for the full length of said carrier, said socket being at the outer end of said carrier and opposite said flat sidelocking surface, said socket and said wedge element decreasing in cross-sectional area toward the outer end of said carrier, the threaded connection of greater lead being between said wedge element and said screw.

11. In the structure defined in claim 7, the side locking surface of said carrier being fiat and extending for the full length of said carrier, said socket being at the inner end of said carrier and opposite said flat side locking surface, said socket and said wedge element decreasing in cross-sectional area toward the outer end of said carrier, the threaded connection of greater lead being between said wedge element and said screw.

12. In the structure defined in claim 7, the side locking surface of said carrier being flat and extending for the full length of said carrier, said socket being at the outer end of said carrier and opposite said flat side locking surface, said socket and said wedge element decreasing in cross-sectionalarea toward the inner end of said carrier, the threaded connection of greater lead being between said screw and said carrier.

13. In a mechanism of the character described, a body having a slot and a cylindrically curved recess intersecting the slot, the axis of said recess being substantially parallel to the side walls of said slot and substantially perpendicular to the slot bottom, a member in said slot, a unitary securing device including a cylindrically curved carrier element slidably fitted-in said recess at one side of said member, said carrier element having at one end a socket that opens laterally,

10 the side wall of said socket being cylindrically curved, a wedge element slidably mounted in said socket, said wedge element having a cylindrically curved side wall portion mated to said socket side wall and further having a side locking surface exposed adjacent the lateral opening of said socket, said carrier element having a side locking surface, and a differential screw having threaded portions of different leads threaded into said carrier element and into said wedge element for interconnecting the same and for actuatingsaid wedge element to move the side locking surfaces of said elements into and out of binding engagement with said member and the wall of said recess, the axes of said socket, said wedge element and said screw being inclined to the axis of said carrier element and the adjacent side of said member.

LEWIS SKEEL.

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